The present invention relates to an improved solvent system for enzymatic coupling processes. In particular, alkylphosphates are employed as a solvent or cosolvent in the enzymatic coupling of amino acids and/or amino acid esters.
The enzymatic coupling of amino acids to form dipeptides and tripeptides has received a lot of attention in recent years due to the increasing commercial utility of these compounds and their relatively high costs of production by chemical processing. Aspartame, a dipeptide, can be made by a variety of chemical processes which are relatively expensive. A more efficient way to produce aspartame (APM) is to enzymatically couple its two amino acid components; i.e., aspartic acid and phenylalanine (Phe) or Phe methyl ester. However, problems are associated with this enzymatic coupling reaction including solubility, recovery and recycling problems. Additionally, many solvent systems are incompatible with enzymes employed in these reactions.
The present invention provides an improved solvent system for enzymatic coupling processes. The improved solvent system is cheap, provides desirable solubility characteristics and allows for easy recovery of solvent. The solvent system can also be easily recycled.